JPH0529566B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a front wheel drive system for a traveling vehicle such as a tractor.

The applicant has filed a patent application filed in 1983 for a front wheel drive device that is small, waterproof, and has low resistance to steering turning operations.
No. 177728, which is proposed as a front axle housing 2 which pivotally supports the shaft 1, as shown in the vertical front view in Fig. 4.
A lower journal boss 4 is formed in the inner gear case 3 attached to the front wheel axle 5, and a lower journal hole 7 is formed in the outer gear case 6 that pivotally supports the front wheel shaft 5, and the journal boss 4 and the journal hole 7 are connected to each other. Since they fit together and make this the steering turning center, the fitting portion between the journal boss 4 and the journal hole 7 is connected to the bevel gear 8 fitted to the front wheel drive shaft 1.
The outer gear case 6 is located below the front axle housing 2 in the lateral direction.
As a result, the lower surface of the outer gear case 6 approaches the ground, lowering the minimum ground clearance in the vicinity of the front wheel drive device of this traveling vehicle. There is a risk of coming into contact with obstacles during agricultural work, etc.
In addition, the inner and outer gear cases 3 and 6 become larger in the vertical direction, and the space near the lower part of the front vehicle body becomes narrower.
I feel inconvenienced during assembly work, inspection work, etc. If the above-mentioned fitting portion is formed to line up on the outside of the bevel gear 8 in the lateral direction, the middle portion 9 of the inner gear case 3 (the journal boss 4 and the mounting base 10 As a result, the inner gear case in this case has a longer lateral length than the one in Figure 4, which is difficult to meet the demand for smaller gear cases. Moreover, the shape of this intermediate portion 9 of the circular gear case is different from that shown in FIG. 4 and is complicated, which is expected to be inconvenient in manufacturing.

Therefore, in view of the above-mentioned deficiencies of the conventional example, the present invention aims to solve the problems by attaching an inner gear case to the outer end of the front axle housing in which the front wheel drive shaft is housed, and forming a gear chamber that opens outward. The planetary gear mechanism is inserted into the gear chamber whose opening is closed by fitting the equipped outer gear case into the inner gear case so as to allow steering rotation, and by attaching the cover that supports the front wheel shaft to the outer gear case. A turning center axis, which is provided rotatably with respect to the inner and outer gear cases so as to coincide with the steering turning center, is connected to the front wheel drive shaft via the inner bevel gear mechanism, and to the outer bevel gear. In the front wheel drive device of a running vehicle, the front wheel drive device is connected to the sun gear of the planetary gear mechanism through a mechanism, and the front wheel axle is configured to be decelerated and driven by the planetary gear mechanism. A gear chamber that is approximately key-shaped in appearance is formed, and the bevel gear attached to the front wheel drive shaft of the inner bevel gear mechanism faces inside this key-shaped vertical part, and the lower part of the inner gear case is located below the gear chamber. A journal boss formed at the lower part of the outer gear case was fitted inside the formed journal hole for steering turning, so that the journal boss was positioned above the lower end of the bevel gear when viewed horizontally. The present invention provides a front wheel drive device for a traveling vehicle characterized by the following. Thus, in the present invention, the lower surface of the outer gear case is raised by the length of the lower journal hole and journal boss arranged side by side on the outer side of the bevel gear, and the minimum ground clearance is also increased. The outer gear case was designed to be smaller.

Next, to explain one embodiment of the present invention, as shown in a vertical front view in FIG. An outer gear case 17 has a substantially key-shaped gear chamber 13, a lower journal hole 15 is formed on the outside of the key-shaped vertical portion 14 of the gear chamber 13, and pivotally supports a front wheel shaft 16. includes a gear chamber 18 that is substantially L-shaped in front cross section and opens outward, and a lower journal boss 1.
9 and an upper journal boss 20 is formed on the upper lid 53 which fits into the upper end opening of the gear chamber 13 of the inner gear case 12.
The inside of the upper journal hole 22 formed in the knuckle arm 21 fixed on the upper part of the knuckle arm 21 is fitted into the upper journal boss 20, and the journal boss 19 is fitted into the inside of the lower journal hole 15. The outer gear case 17 is formed to be rotatable with respect to the inner gear case 12, and the rotation center axis 23 is formed in a substantially key shape so as to coincide with the cylindrical center of the upper and lower journal bosses 20, 19. Looking into the horizontal portion 24, the bevel gear 26 is pivotally supported on the upper part of the inner gear case 12 by a bearing 25, and the bearing 27
A bevel gear 29 extending into the vertical portion 14 of the gear chamber 13 is fitted onto the outer end of the front wheel drive shaft 10 which is rotatably supported by the outer gear case 17 via a bearing 28. , an inner bevel gear mechanism 30 consisting of bevel gears 29 and 26.

The front wheel axle 16 has a front wheel 31 and a carrier 32 fitted in the gear chamber 18, and an outer cover 35 which pivotally supports the front wheel axle 16 by a bearing 33 and a bearing 34 fitted to the carrier 32. is attached to the outer end of the outer gear case 17, and a sun gear 37 formed by integrally connecting with a large-diameter bevel gear 36 is loosely fitted to the inner part of the front wheel axle 16 via bearings 38, 38, and An internal gear 39 is attached to the portion of the cover 35 that looks into the gear chamber 18, and planetary gears 42 are loosely fitted through bearings 41 to a plurality of fixing pins 40 arranged and fixed to the carrier 32. Internal gear 39 and sun gear 3
7, the planetary gear mechanism 44 and the bevel gear 36 are housed in the approximately L-shaped vertical portion 43 of the gear chamber 18, and the rotation center axis is located within the horizontal portion 51 of the gear chamber 18. A bevel gear 45 fitted to the lower part of the bevel gear 23 meshes with the bevel gear 36 to form an outer bevel gear mechanism 46.

Further, in the illustrated example, the fixing pin 40 is fixed to the carrier 32 with a bolt 48 through a rotation prevention plate 47 that engages with a notch provided in the fixing pin 40, and a bevel gear 26
The center axis of rotation 2 is secured by the holding plate 49 and the bolt 50.
It is stopped moving at 3. And the vertical load is
The load is borne by a thrust bearing 52 interposed between the upper end of the lower journal boss 19 and the upper end of the lower journal hole 15. When the arm portion of the nut arm 21 is rotated by a steering mechanism (not shown), the outer gear case 17 and the front are rotated about the upper journal boss 20, the lower journal boss 19, and the rotation center axis 29. When the wheel axle 16 and the front wheels 31 turn, and the front wheel drive shaft 10 is driven by a front wheel differential gear mechanism (not shown), the sun gear 37 is decelerated and driven via the bevel gear mechanisms 30 and 46. , and the planetary gear 42
...and the internal gear 39, the carrier 32
is further decelerated, so the front wheel axle 16 is driven at a sufficiently decelerated rotational speed.

In the embodiment shown in FIG. 2, the sun gear shaft 22 has the sun gear 21 and the bevel gear 20 molded from a single piece of material, but it is possible to manufacture both gears separately and make one unit. They may be combined together.

The front wheel drive device for a traveling vehicle according to the present invention is configured as described above, and is provided in the vertical portion 14 of the gear chamber 13 of the inner gear case 12 whose front cross section is formed into an approximately inverted L shape. A lower journal hole 15 is formed in the inner gear case 12 near the outer side of the bevel gear 29 on the side of the front wheel drive shaft 10 as seen.
Since the fitting portion of the lower journal boss 19 formed on the outer gear case 17 is positioned, there is no need to increase the width of the inner and outer gear cases 12 and 17, and the front wheel drive shaft 10 and its front axle housing 11 can be On the other hand, the lower part of the outer gear case 17 equipped with the lower journal boss 19 has come to be sufficiently close to each other, and as a result, the position of the lower surface of the outer gear case 17 has become higher, as described above. Compared to the previously proposed drive device in which the lower journal hole 7 and the journal boss 4 are located below the height of the bevel gear 8 on the front wheel drive shaft 1 side, in the present invention, the lower journal hole 7 and the journal boss 4 are located below the height of the bevel gear 8 on the front wheel drive shaft 1 side. The lower surface of the outer gear case 17 is raised by the length that the fitting portion of the outer gear case 15 and the journal boss 19 are arranged horizontally on the outer side of the bevel gear 29, which is a factor in determining the minimum ground clearance near the front wheel drive device. This invention makes it possible to raise the lower surface position of the outer gear case 17, which is extremely advantageous for work over ridges, etc.
17 is also compact, making it possible to widen the space near the lower front body of a running vehicle, which tends to be narrow, making it convenient for assembly work or inspection work during use, and further reducing the size. This made the production cost low.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a side view of a tractor as an example of a traveling vehicle, FIG. 2 is a longitudinal sectional front view of a front wheel drive device,
FIG. 3 is a sectional view taken along the line A--A in FIG. 2, and FIG. 4 is a longitudinal sectional front view of the conventional front wheel drive device. Description of symbols, 10...Front wheel drive shaft, 11...Front axle housing, 12...Inner gear case, 1
3, 18... Gear chamber, 14... Vertical portion, 15... Journal hole, 16... Front wheel axle, 17... Outer gear case,
19... Journal boss, 23... Rotation center axis, 3
0, 46... Bevel gear mechanism, 37... Sun gear, 4
4... Planetary gear mechanism.

Claims (1)

[Claims] 1. Attach an inner gear case to the outer end of the front axle housing that houses the front wheel drive shaft, and fit the outer gear case, which has a gear chamber that opens outward, into the inner gear case so that the steering can be rotated freely. A planetary gear mechanism is installed inside the gear chamber whose opening is closed by attaching a cover that supports the wheel shaft to the outer gear case, and the planetary gear mechanism is aligned with the center of steering turning and is attached to the inner and outer gear cases. A rotatably provided rotation center shaft is connected to the front wheel drive shaft via an inner bevel gear mechanism and to a sun gear of the planetary gear mechanism via an outer bevel gear mechanism, and the rotation center shaft is connected to the planetary gear mechanism. Therefore, in a front wheel drive device for a traveling vehicle configured to drive the front wheel axle at a reduced speed, a gear chamber having a substantially key-shaped front cross-sectional view is formed in the inner gear case. The bevel gear attached to the front wheel drive shaft of the inner bevel gear mechanism is exposed, and the steering turning journal hole formed at the bottom of the inner gear case is placed below the gear chamber, and the steering turning journal hole is formed at the bottom of the outer gear case. Fit the journal boss,
A front wheel drive device for a traveling vehicle, characterized in that the journal boss is located above a lower end of the bevel gear when viewed horizontally.